'use strict';

const async = require('async');
const _ = require('lodash');
const path = require('path');
const nconf = require('nconf');

const db = require('../database');
const posts = require('../posts');
const topics = require('../topics');
const groups = require('../groups');
const messaging = require('../messaging');
const plugins = require('../plugins');
const batch = require('../batch');
const file = require('../file');

module.exports = function (User) {
	const deletesInProgress = {};

	User.delete = async (callerUid, uid) => {
		await User.deleteContent(callerUid, uid);
		await removeFromSortedSets(uid);
		return await User.deleteAccount(uid);
	};

	User.deleteContent = async function (callerUid, uid) {
		if (parseInt(uid, 10) <= 0) {
			throw new Error('[[error:invalid-uid]]');
		}
		if (deletesInProgress[uid]) {
			throw new Error('[[error:already-deleting]]');
		}
		deletesInProgress[uid] = 'user.delete';
		await deletePosts(callerUid, uid);
		await deleteTopics(callerUid, uid);
		await deleteUploads(uid);
		await deleteQueued(uid);
	};

	async function deletePosts(callerUid, uid) {
		await batch.processSortedSet('uid:' + uid + ':posts', async function (ids) {
			await async.eachSeries(ids, async function (pid) {
				await posts.purge(pid, callerUid);
			});
		}, { alwaysStartAt: 0 });
	}

	async function deleteTopics(callerUid, uid) {
		await batch.processSortedSet('uid:' + uid + ':topics', async function (ids) {
			await async.eachSeries(ids, async function (tid) {
				await topics.purge(tid, callerUid);
			});
		}, { alwaysStartAt: 0 });
	}

	async function deleteUploads(uid) {
		await batch.processSortedSet('uid:' + uid + ':uploads', async function (uploadNames) {
			await async.each(uploadNames, async function (uploadName) {
				await file.delete(path.join(nconf.get('upload_path'), uploadName));
			});
			await db.sortedSetRemove('uid:' + uid + ':uploads', uploadNames);
		}, { alwaysStartAt: 0 });
	}

	async function deleteQueued(uid) {
		await batch.processSortedSet('post:queue', async function (ids) {
			const data = await db.getObjects(ids.map(id => 'post:queue:' + id));
			const deleteIds = data.filter(d => parseInt(d.uid, 10) === parseInt(uid, 10)).map(d => d.id);
			await async.eachSeries(deleteIds, posts.removeFromQueue);
		}, { alwaysStartAt: 0 });
	}

	async function removeFromSortedSets(uid) {
		await db.sortedSetsRemove([
			'users:joindate',
			'users:postcount',
			'users:reputation',
			'users:banned',
			'users:banned:expire',
			'users:flags',
			'users:online',
			'users:notvalidated',
			'digest:day:uids',
			'digest:week:uids',
			'digest:month:uids',
		], uid);
	}

	User.deleteAccount = async function (uid) {
		if (deletesInProgress[uid] === 'user.deleteAccount') {
			throw new Error('[[error:already-deleting]]');
		}
		deletesInProgress[uid] = 'user.deleteAccount';

		await removeFromSortedSets(uid);
		const userData = await db.getObject('user:' + uid);

		if (!userData || !userData.username) {
			delete deletesInProgress[uid];
			throw new Error('[[error:no-user]]');
		}

		await plugins.fireHook('static:user.delete', { uid: uid });
		await deleteVotes(uid);
		await deleteChats(uid);
		await User.auth.revokeAllSessions(uid);

		const keys = [
			'uid:' + uid + ':notifications:read',
			'uid:' + uid + ':notifications:unread',
			'uid:' + uid + ':bookmarks',
			'uid:' + uid + ':followed_tids',
			'uid:' + uid + ':ignored_tids',
			'user:' + uid + ':settings',
			'user:' + uid + ':usernames',
			'user:' + uid + ':emails',
			'uid:' + uid + ':topics', 'uid:' + uid + ':posts',
			'uid:' + uid + ':chats', 'uid:' + uid + ':chats:unread',
			'uid:' + uid + ':chat:rooms', 'uid:' + uid + ':chat:rooms:unread',
			'uid:' + uid + ':upvote', 'uid:' + uid + ':downvote',
			'uid:' + uid + ':flag:pids',
			'uid:' + uid + ':sessions', 'uid:' + uid + ':sessionUUID:sessionId',
			'invitation:uid:' + uid,
		];

		const bulkRemove = [
			['username:uid', userData.username],
			['username:sorted', userData.username.toLowerCase() + ':' + uid],
			['userslug:uid', userData.userslug],
			['fullname:uid', userData.fullname],
		];
		if (userData.email) {
			bulkRemove.push(['email:uid', userData.email.toLowerCase()]);
			bulkRemove.push(['email:sorted', userData.email.toLowerCase() + ':' + uid]);
		}

		await Promise.all([
			db.sortedSetRemoveBulk(bulkRemove),
			db.decrObjectField('global', 'userCount'),
			db.deleteAll(keys),
			db.setRemove('invitation:uids', uid),
			deleteUserIps(uid),
			deleteBans(uid),
			deleteUserFromFollowers(uid),
			groups.leaveAllGroups(uid),
		]);
		await db.deleteAll(['followers:' + uid, 'following:' + uid, 'user:' + uid]);
		delete deletesInProgress[uid];
		return userData;
	};

	async function deleteVotes(uid) {
		const [upvotedPids, downvotedPids] = await Promise.all([
			db.getSortedSetRange('uid:' + uid + ':upvote', 0, -1),
			db.getSortedSetRange('uid:' + uid + ':downvote', 0, -1),
		]);
		const pids = _.uniq(upvotedPids.concat(downvotedPids).filter(Boolean));
		await async.eachSeries(pids, async function (pid) {
			await posts.unvote(pid, uid);
		});
	}

	async function deleteChats(uid) {
		const roomIds = await db.getSortedSetRange('uid:' + uid + ':chat:rooms', 0, -1);
		const userKeys = roomIds.map(roomId => 'uid:' + uid + ':chat:room:' + roomId + ':mids');

		await Promise.all([
			messaging.leaveRooms(uid, roomIds),
			db.deleteAll(userKeys),
		]);
	}

	async function deleteUserIps(uid) {
		const ips = await db.getSortedSetRange('uid:' + uid + ':ip', 0, -1);
		await db.sortedSetsRemove(ips.map(ip => 'ip:' + ip + ':uid'), uid);
		await db.delete('uid:' + uid + ':ip');
	}

	async function deleteBans(uid) {
		const bans = await db.getSortedSetRange('uid:' + uid + ':bans:timestamp', 0, -1);
		await db.deleteAll(bans);
		await db.delete('uid:' + uid + ':bans:timestamp');
	}

	async function deleteUserFromFollowers(uid) {
		const [followers, following] = await Promise.all([
			db.getSortedSetRange('followers:' + uid, 0, -1),
			db.getSortedSetRange('following:' + uid, 0, -1),
		]);

		async function updateCount(uids, name, fieldName) {
			await async.each(uids, async function (uid) {
				let count = await db.sortedSetCard(name + uid);
				count = parseInt(count, 10) || 0;
				await db.setObjectField('user:' + uid, fieldName, count);
			});
		}

		const followingSets = followers.map(uid => 'following:' + uid);
		const followerSets = following.map(uid => 'followers:' + uid);

		await Promise.all([
			db.sortedSetsRemove(followerSets.concat(followingSets), uid),
			updateCount(following, 'followers:', 'followerCount'),
			updateCount(followers, 'following:', 'followingCount'),
		]);
	}
};
